Anonymous Bulgaria has issued an ultimatum to US energy giant Chevron over its expanding shale gas exploration activities on Romanian territory.

The local unit of Anonymous warned in a Tuesday statement that by the end of the day the website of the energy corporation would collapse, showing its executives that their activities would not go unpunished.

The group, as cited by Sega daily, vowed that it would keep battling "forces of the New World Order which place money above blood and nature."

They explained that they had targeted Chevron because they were seeking to boost profits and "appease their bottomless corporate greed" through impudent destruction of land and water belonging to other peoples.

The activists noted that the imposition of a ban on shale gas drilling through hydraulic fracturing (fracking) in Bulgaria had caused the "destroyers of nature" to move to Romania.

"The fracking zones are in northern Dobrudzha, which is almost the same as if they were in Bulgaria," they insisted.

They argued that hydraulic fracturing lead to soil and water contamination in 99% of the cases and could even trigger earthquakes.

The activists pledged to not leave Chevron's looting would not be left unretaliated.